High performance plastics, in particular poly(ether ketone) polymers, due to their attractive properties, are currently used for the manufacture of several parts and articles as replacement for materials like metals, alloys and the like. Poly(ether ether ketone) (PEEK), for instance, is well known as an ultra-performance polymer. It is a semi-crystalline, highly chemically resistant, fatigue resistant and dimensionally stable material at high temperatures.
In the design and synthesis of high performance plastics, rigid aromatic groups are typically used to impart attributes such as thermal stability and mechanical strength. The rigidity of these groups contributes to high glass transition temperatures and/or melting points and also provides the thermal stability needed for processing at increased temperature. While rigid aromatic groups provide for increased thermal and mechanical performance, the trade-off is usually a decrease in the UV and photo-oxidative stability of the resultant polymers. In the past, incorporation of aliphatic monomers into high performance polymers has been used to increase UV/photo-oxidative stability. Unfortunately, addition of aliphatic monomers generally leads to a decrease in other attributes.
It has now been found that poly(ether ketone) polymers comprising monomeric units derived from aliphatic diols comprising cycloaliphatic units, in particular from 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO), are still characterised by a good balance of properties required by high performance plastics, such as high glass transition temperatures and/or melting temperatures without suffering from the UV and photo-oxidative limitations of polymers containing monomeric units comprising rigid aromatic groups only.